First Dr's appointment question

RR • Together since 2009 | Married since 2014 | 3 M/C`s | MTHFR | Rainbow baby born 07/02/17💗 #2 Due 12/21/20!!
I got my BFP last night! Yay!! So excited. I called the Dr this morning they want me to go in today. They're just going to do a pregnancy test, right? The last two BFP's I had ended in MC and I never made it to the Dr before the bleeding began. So I don't know what to expect. I'm thinking I'm about 3 or 4 weeks. So really early. <a href="https://play.google.com/store/apps/details?id=com.glow.android.nurture">Due date calculator</a> says May 20,2016. 
What should I expect from this appointment and when would the first US be?
Thanks in advance!